ES2201278T3 - DEVICE FOR MAINTAINING A CHASSIS AT LEVEL. - Google Patents

Abstract

The invention concerns a device for maintaining at an adjusted level the chassis of a vehicle with variable suspension, comprising: means for variable unfolding (1) fixed by one of their ends on the chassis such that the other end rests, at least when these means are unfolded, on an axle (20) of the vehicle; first control means (14) for controlling the unfolding of the variable unfolding means (1); second control means (5, 9) for increasing the pressure of a first fluid contained in the elements of the variable suspension in response to a load increase applied to the chassis; and third control means (9) for reducing the pressure of the first fluid contained in the elements of the variable suspension in response to a load decrease applied to the chassis.

Description

Device to keep a chassis level.

The present invention relates in a manner general to a maintenance device at a set level of a chassis of a vehicle with variable suspension, to a vehicle that comprises said device as well as a method of maintenance at a tight level of a vehicle chassis with variable suspension

When loading and unloading of a vehicle such as a truck, a trailer or a semi-trailer, the The level of the loading platform of this vehicle may vary to As the loading platform is filled with or emptied of, the commodity. While this platform level variation of loading does not matter when loading and unloading is perform without penetration of a car or the like on the platform of the vehicle, it raises important problems when loading and the unloading is done by means of a cargo vehicle such such as an elevator car, which penetrates the vehicle platform to deposit or extract merchandise.

Indeed, when a vehicle is placed in the dock, the loading platform can go up or down, during the loading or unloading, with respect to the loading dock at a height of the order of 15 to 20 cm. This approximate value depends on the load applied, loading or unloading conditions and stiffness vehicle. Said unevenness may constitute a source of accidents, taking into account the risk of tilting the car of load when the passage of this slope takes place. At least, this unevenness constitutes an obstacle to overcome that causes a Substantial slowdown in the loading and unloading of the vehicle.

A vehicle that has a chassis and at least one shaft attached to the chassis by hydraulic shock absorbers variable connected to a first source of a first fluid is known from EP-A-0 517 546 corresponding to the preamble of claim 1. This vehicle comprises a maintenance device at a level adjusted by means of control intended to increase or reduce the pressure of the first fluid contained in the shock absorbers to keep the chassis at a predetermined level. The vehicle also comprises variable deployment means that  comprise a hydraulic suspension damper that contains a second fluid and that is fixed by one of its ends on the chassis and the other end of the shaft. The device of maintenance at a tight level comprises first means of command intended to send the deployment of the deployment means variable, and a few second command means intended to increase the pressure of the first fluid contained in the shock absorbers until the pressure on the means of variable deployment is no longer higher than the first fluid contained in the shock absorbers.

The objective of the invention is to avoid this inconvenient and propose a device capable of maintaining the loading platform of a vehicle at a level that has been adjusted before loading or unloading this vehicle.

The invention achieves this objective by characteristics of the second part of claim 1.

Within the framework of the present invention, the term "variable suspension" includes all types of suspensions designed to allow varying the level of loading platform of a stationary vehicle with respect to I usually.

Thus, the device of the invention can be applied to vehicles with air suspension, which corresponds to most vehicles whose platform level Charging can be regulated. It is similarly applicable. to vehicles with hydraulic suspension and mixed suspension hydraulic / pneumatic

Also, although the invention is described in continued with reference to a vehicle that has only one axle (case of a semi-trailer) or a single rear axle (case of a truck or trailer), it is also applicable to a vehicle that has several axles. In that case, the vehicle can be equipped with one or more devices depending on the invention.

The device of the invention comprises about variable deployment means, such as for example one or more cats According to the invention these means are fixed only. on the chassis by only one of its ends, the other being free end and supported only after deployed on the axis.

The deployment of deployment media variable, when they consist of one or more cats, It consists of deploying the mobile part of the cat (s) in make them rest on the shaft, if the fixed part is mounted on the chassis, and in blocking or blocking them in this position of support for.

The control means intended respectively for increase and reduce the fluid pressure contained in these elements of the variable suspension can be, for example, about pressure switches and end-of-race sensors.

The maintenance device according to the invention is energetically autonomous, the source of energy is advantageously compressed air that comes from the system of braking, or pneumatic suspension system. Thus, the maintenance device can work, when mounted on a trailer or semi-trailer, with the tractor attached or disengaged. Taking into account the use of the device maintenance according to the invention as a means of blocking the suspension at the adjusted level, this device is usable in the suspension displacement zone.

The invention also relates to following characteristics, considered in isolation or according to all their technically possible combinations:

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The device comprises, when the variable deployment means are consisting of at least one cat, a support detector attached to the first and third means of command, in order to stop their actions when the cat (s) rest on the axis.

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The support detector is attached to the third means of command so that it can shoot your action when the cat (s) are not resting on the axis.

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The cat is a cat hydraulic that contains a second fluid. This second fluid that it is advantageously a hydraulic oil, it can be contained in a separate circuit of the braking circuits and of suspension.

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The first fluid is compressed air that comes from a first air source compressed. This first source of compressed air can be a pressure tank, such as the pneumatic circuit tank of the compressed air braking system, or a separate tank of compressed air to which a circuit is also connected rises and low required to adjust the platform level of the vehicle. The filling of the pressure tank can be done automatically or by manual command.

The conception of the maintenance device a an adjusted level such as the one described here is advantageously simplified when used as a source of energy, only compressed air. However, as has been shown above, an electric power supply or hydraulic in case of application in an electric vehicle or in a vehicle equipped with a hydraulic power plant is also conceivable.

The objective of the invention is achieved by a vehicle that has a chassis and at least one axle coupled to the chassis by elements of a variable suspension connected to a first source of a first fluid, this vehicle comprising a maintenance device such as defined more above.

In such a vehicle, the means of deployed variable can be connected to an accumulator of transfer containing compressed air that comes from a First source of compressed air.

The vehicle according to the invention can be a semitrailer.

The objective of the invention is also achieved. by a maintenance procedure at a set level of a chassis of a vehicle with variable suspension. This procedure, which can be applied indifferently to vehicles with pneumatic, hydraulic or mista pneumatic / hydraulic suspension and a some vehicles that have one or more axles, include the stages:

(to)

put a loading platform that belongs to the chassis at the same level as a loading dock, acting on suspension elements variable that allow raising and lowering the chassis level,

(b)

lock the chassis at the adjusted level acting on variable deployment means fixed by one of its ends on the chassis, so that the another of its extremes is supported, at least in the deployed state of these means, on an axle of the vehicle attached to the chassis by the variable suspension elements,

(c)

when it applies a load on the chassis that has the effect that the pressure on the variable deployment means exceeds a first limit value, increase the pressure of a first fluid contained in the elements of the variable suspension until the pressure on the means of variable display no longer exceeds the first value limit,

(d)

when the load applied to the chassis is reduced, having the effect that the means Variable unfolding are no longer in contact with the shaft, reduce the first fluid pressure of the suspension elements variable until the variable deployment media is again in contact with the shaft,

(and)

repeat the stages (c) and (d) as many times as necessary for the duration of a load or unloading of the vehicle,

(F)

at the end of the loading or unloading of the vehicle, unlock the chassis acting on Variable deployment media.

As stated above, the means of variable display may consist of one or more cats Depending on the type of media used, the stage consisting of act on variable deployment means, includes the deployed or retraction in case of using cats.

Other features and advantages of the invention will stand out from the description of an example of realization of a maintenance device according to the invention given below with reference to the attached plans, in which:

Figure 1 represents the scheme of a maintenance device at a level adjusted according to the invention,

Figure 2 represents a first variant of the device of figure 1, and

Figure 3 represents a second variant of the device of figure 1.

The maintenance device according to the invention, also referred to below as "circuit of block "is described using the same numbers of reference for identical components. Thus, the circuit of lock comprises two hydraulic jacks 1 mounted by one of its ends to the chassis 10 of the vehicle, and oriented such that, when cats are deployed, their free ends are supported on axis 20.

Hydraulic jacks 1 are connected by a hydraulic circuit to a transfer accumulator 3. Between hydraulic jacks 1 and transfer accumulator 3 is inserted a valve distributor 4 with pneumatic control normally closed. In addition, cats are connected by a hydraulic line to a pneumatic control load pressure switch 5.

The support of jacks 1 on axis 20 as well as the separation of the jacks from the shaft are detected by means of two limit switches 6 of pneumatic control connected to a pneumatic logic cell "ET" 61 in order to signal support only when the two jacks are supported on axis 20.

The blocking circuit is connected to a brake tank 50 provided with a shut-off valve 51 and a circuit "goes up and down" 60 and includes, in addition to a filter control air lubricator 7, a pneumatic logic cell "INHIBITION" 8 connected to switches 6, a distributor of pneumatic control valve 9 for inflation and deflation of the air cushions 40 of the air suspension, some cells Pneumatic logic "OU" 11, "ET" 12 and "INHIBITION" 13, as well as a pneumatic rotary knob selector switch 14. Selector 14 allows you to choose the operating modes of the blocking circuit, namely "Descent of the cats" D, "Suspension lock" B and "Rise of cats" R.

The blocking circuit finally comprises a pneumatic control distributor 16 spring return and whose center is open to escape. A pneumatic light pilot 17 intended to signal the arrival in contact of jacks 1 with the shaft 20 as well as a verification circuit that allow to verify the presence of pressure in the braking system complete this blocking circuit

The verification circuit is connected to a brake vessel 52 and a braking service line 53 and ones pneumatic logic cells "OU" 54 and "INHIBITION" 55.

The different components of the circuit lock listed above are connected according to the scheme represented in figure 1 so that they allow next operation of the maintenance device a level.

When the vehicle is in running position, the rotary button pneumatic control selector 14 is in position "Rise of the cats" and distributor 16 is kept in "Climbing the cats" position.

When the vehicle is in the position of parking, engaged or not, the brake tank 50 is at Pressure. The valve distributor 4 is in position normally closed and prevents cats 1 from unfolding.

When the vehicle is parked along a loading dock, the level of the loading platform 30 is adjusted of the vehicle, by means of the circuit up and down 60 of the vehicle, with the dock Having adjusted the level, the suspension is locked by turning the suspension lock control button 14 on position "Descent of the cats". By this command, cats 1 They are deployed.

Since cats 1 come into contact with the axis 20, indicated by the lighting of pilot 17, the control button 14 is turned to the "Suspension lock" position. For that is, the jacks are isolated from the blocking circuit.

The operation of the device level maintenance is then different depending on whether it is vehicle loading or unloading the vehicle.

In case of vehicle loading, operation The device is as follows.

When a cargo vehicle, such as a car elevator, which carries a payload goes up on platform 30 of the vehicle, jacks 1 prevent the descent of the suspension, which increases the pressure "Pv" of the jacks 1. If the pressure "Pv" is higher than a trigger pressure "Po" of pressure switch 5, it is sent air to the air cushions 40 of the suspension until the cat pressure "Pv" is less than a pressure of "Pr" reset of pressure switch 5.

When the car, after having deposited its payload on the vehicle, leave the latter, the new pressure on the air cushions 40 is too important with respect to the load. Consequently, the platform 30 of the vehicle rises and the cats 1 are no longer in contact with axis 20. This loss of support is detected by the limit switches 6 whose Switched position allows air leakage from the air cushions 40 via valve distributor 9 until jacks 1 are rest on axis 20 again.

This succession of swelling and deflation of Air cushions will be repeated until the load is finished. To the end of loading, the rotary button selector 14 is set to the position "Rise of the cats". Cats 1 are retracted and They are locked in their stowed position. Following this, the vehicle can be unraveled and put into gear position.

When a vehicle unloading takes place put on the dock, the operation of the device Maintenance is as follows.

When an empty car penetrates the platform 30 of the vehicle, jacks 1 prevent the descent of the suspension. At the same time, the pressure of the cat "Pv" increases, without cause an increase in pressure of the air cushions 40, since the pressure of the "Pv" cats does not exceed the pressure of "Po" shot of pressure switch 5.

When the car, after taking on load a payload, leave the platform 30 of the vehicle, the platform it rises and jacks 1 are no longer in contact with the shaft. Is loss of support is verified by means of switches 6 which they fire the air escape from the air cushions 40 by means of the valve distributor 9 until jacks 1 are supported again on axis 20.

The pressure reduction of the cushions suspension is caused as many times as the car pulls load vehicle useful.

When the download is finished, the selector button 14 is put in position "Rise of the cats", the cats are retracted and locked in the stowed position and the vehicle is unraveled and put in running position.

Figure 2 represents, in a variant of the maintenance device described above, a device of maintenance at a level adjusted according to the invention in which the variable deployment means are constituted by a single cat.

According to this variant the blocking circuit differs from that described with reference to figure 1, in that It comprises a single hydraulic jack 1 mounted at one end to the chassis 10 of the vehicle.

This hydraulic jack 1 is connected to the transfer accumulator 3 and load pressure switch 5 so analogous to that of the blocking circuit according to figure 1.

The support of jack 1 on axis 20 as well as the jack separation from the shaft is detected by a single switch Race 6 end of pneumatic control. This switch 6 is connected directly to the pneumatic light pilot 17 and the pneumatic logic cells "ET" and "INHIBITION" 13 that send pressure switch 5 and valve distributor 9.

The operation of the blocking circuit according to this variant corresponds to that of the blocking circuit represented in figure 1.

Figure 3 represents, as a second variant of the maintenance device described with reference to figure 1, a maintenance device at a level adjusted according to the invention in which the operating regimes of the circuit of blocking, namely the descent of the cats, the blocking of the suspension and rise of cats, are sent by a manual control distributor 116 whose center is open to the exhaust. The distributor 116 is interlockable by spring return to the point medium.

The verification circuit, which is connected to the brake valves 52 and the brake service line 53, it comprises a pneumatic pneumatic control distributor 180 and a pneumatic logic cell "INHIBITION" 13 instead of cells Logic 8, 54 and 55 described above.

On the other hand, the variant represented in the Figure 3 comprises, instead of a single distributor 9 for the swollen and deflated air cushions 40 of the air suspension, distributors with individual valves 91 and 92 for each of the air cushions 40 of the suspension pneumatics.

The operation of the blocking circuit according to this second variant corresponds, apart from the manual control in place of the pneumatic control, to that of the represented blocking circuit in figure 1.

The reference signs inserted after the technical characteristics mentioned in the claims, Their sole objective is to facilitate the understanding of these last, and in no way limit its scope.

Claims (9)

1. Vehicle having a chassis (10) and at least one axle (20) attached to the chassis by elements (40) of a variable suspension connected to a first source (50) of a first fluid, the vehicle comprising a device of maintenance at an adjusted level intended to intervene when the chassis level has been adjusted by means of the elements (40) of the variable suspension, the device comprising variable unfolding means (1) fixed by one of its ends on the chassis (10) and first control means (9, 91, 92) intended to command the deployment of the variable unfolding means to block the chassis at the level adjusted by the elements (40) of the variable suspension, characterized in that the means of Variable deployed (1) are fixed only on the chassis (10) so that the other of its free ends is supported, in the deployed state of these means, on the shaft (20), and because the device comprises:

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a few second means command (5, 9, 91, 92) designed to detect if the pressure (Pv) on the variable deployment means (1) exceeds a first limit value (Po) due to an increase in the load applied to the chassis and to increase the pressure of a first fluid contained in the elements of the variable suspension (40) until the pressure on the means of variable deployment (1) no longer exceeds first limit value;

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a third means command (6, 9, 91, 92) intended to detect whether the means of variable display (1) are no longer in support on the axis (20) to cause of a reduction in the load applied to the chassis and for reduce the pressure of the first fluid contained in the elements of the variable suspension (40) until the deployment means variable be in contact with the axis again.

2. A vehicle according to claim 1, characterized in that the variable deployment means comprise at least one jack (1). 3. Vehicle according to claim 2, characterized in that it comprises a support detector (6) connected to the first (14, 116) and the third control means (9) and intended to stop its action when the jack rests on the axle (twenty). A vehicle according to claim 3, characterized in that the support detector (6) is connected to the third control means (9) so that it can trigger its action when the jack is not supported on the axle (20). 5. Vehicle according to any of claims 2 to 4, characterized in that the jack (1) is a hydraulic jack containing a second fluid. A vehicle according to any one of the preceding claims, characterized in that the first fluid is compressed air that comes from a source of compressed air (50) of a pneumatic circuit of the vehicle. A vehicle according to claim 1, characterized in that the variable deployment means are connected to a transfer accumulator (3) containing compressed air that comes from the first source (50) of a first fluid that is compressed air. 8. Vehicle according to claim 7, characterized in that it is a semi-trailer. 9. One level maintenance procedure adjusted of a chassis of a vehicle with variable suspension, which It comprises the stages of:

to)

put the chassis to same level as a loading dock, acting on elements of the variable suspension that allow to raise and lower the level of chassis;

b)

lock the chassis at the adjusted level acting on variable deployment means fixed by one of its ends on the chassis, so that the another of its extremes is supported, at least in the deployed state of these means, on an axis of the vehicle attached to the chassis by the elements of the variable suspension;

c)

when it applies a load on the chassis that has the effect that the pressure on variable deployment means exceeds a first limit value, increase the pressure of a first fluid contained in the variable suspension elements until the pressure on the variable display means no longer exceeds the first value limit;

d)

when the load applied to the chassis is reduced, having the effect that the means Variable unfolding are no longer in contact with the shaft, reduce the pressure of the first fluid contained in the elements of the variable suspension until variable deployment means are in contact with the shaft again;

and)

repeat the stages c) and d) as many times as necessary for the duration of a loading or unloading of the vehicle;

F)

at the end of the loading or unloading of the vehicle, unlock the chassis acting on Variable deployment media.